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For refcode 1989AJ.....97.1291N:
Retrieve 72 NED objects in this reference.
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1989AJ.....97.1291N EVOLUTION OF RADIO QUASARS FOR z < 2 S. G. NEFF Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 J. B. HUTCHINGS Dominion Astrophysical Observatory, National Research Council of Canada, 5071 W. Saanich Road, Victoria, British Columbia V8L 4M6, Canada ANN C. GOWER Department of Physics and Astronomy, University of Victoria, P.0. Box 1700, Victoria, British Columbia V8W 2Y2, Canada Received 15 July 1988; revised 28 December 1988 ABSTRACT A sample of 72 radio quasars has been selected to fill the redshift range 1-2 evenly and the (total) 2.7 GHz luminosity range as widely and evenly as possible, with no knowledge of any other property (e.g., spectral index, morphology). A-configuration VLA observations of the sample are used to study the distribution of source morphology and other properties in the redshift/luminosity plane. These results, and those from a similarly selected sample of z = 0.35-1.0 objects previously observed, are used to investigate the cosmic and individual evolution of quasars to redshift 2. We find that the most luminous sources at all redshifts are unresolved, and that one-sided and two-sided structures correspond to progressively lower core (and total) luminosities. We propose that this sequence represents the general evolution of individual quasars. Earlier epoch sources are smaller and slightly more bent, although these properties do not change greatly above z = 1.3. The sizes and fractional population of triple sources fall steadily with increasing redshift to z ~ 1.7, but may rise somewhat at the highest redshifts studied. Our results in these respects differ from those based on a sample of steep spectrum sources only. We also present and discuss evidence for mild beaming of core and lobe radiation, and for alternating ejection by the central core. We find that there is a correlation over many orders of magnitude between the optical and maximum radio-core luminosity.
Retrieve 72 NED objects in this reference.
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